The present invention relates to an electrophotographic apparatus for obtaining full color image.
As can be seen from Japanese Patent Application Laid-Open No. 5-66660(1993), the conventional color printer is provided with a cam and its drive mechanism for selectively urging a developer onto a photo conductor within a lid to be opened and closed upon exchanging the developer.
On the other hand, as can be seen from Japanese Patent Application Laid-Open No. 2001-83801, a shaft with two gears for driving the developer is provided below the developer to mesh these gears with gears on both sides of the developer for biasing the developer onto the photo conductor by rotation of the shaft.
In Japanese Patent Application Laid-Open No. 5-66660(1993), since the cam and its drive mechanism for urging the developer onto the photo conductor are provided within the lid, the lid inherently becomes complicate and heavy.
On the other hand, in the example illustrated and disclosed in Japanese Patent Application Laid-Open No. 2001-83801, since the shaft is provided below the developer, an interval between the developers has to be wide enough to make a height of a printer body high.
The present invention has been worked out for solving the problem set forth above. Therefore, it is an object of the present invention to provide a color electrographic apparatus which can simplify a structure and reduce weight of as lid and can reduce necessary height of a printer body.
According to the first aspect of the present invention, a color electrophotographic apparatus having a photo conductor and a plurality of detachable developers, comprises:
rotation transmitting means provided on both sides of each of the developers and cooperated with each other, for transmitting rotational force, one of the rotation transmitting means driving the developer; and
a brake mechanism controllable for turning ON and OFF the other rotation transmitting means.
In the preferred construction, the brake mechanism starts slippage at a predetermined torque or force.
According to the second aspect of the present invention, a color electrophotographic apparatus having a photo conductor and a plurality of detachable developers, comprises:
gears provided on both sides of each of the developers and cooperated with each other,
rotation transmitting means meshed with one of the gears, for driving the developer,
another rotation transmitting means having a brake mechanism starting slippage at a predetermined torque or force and meshing with the other gear one of the rotation transmitting means driving the developer; and
the brake mechanism being controllable for turning ON and OFF the another rotation transmitting means.
The brake mechanism may be turned ON when the developer is contacted with the photo conductor, the brake mechanism is turned OFF when developer is released away from the photo conductor. The brake mechanism may be positioned below the developer
According to the third aspect of the present invention, a color electrophotographic apparatus having a photo conductor and a plurality of detachable developers, comprises:
rotation transmitting means provided on both sides of each of the developers and cooperated with each other, for transmitting rotational force, one of the rotation transmitting means driving the developer; and
a brake mechanism starting slippage at a predetermined torque or force being provided in the other rotation transmitting means, the brake mechanism being mounted on the developer.
The rotation transmitting means may include at least one or more gears.
The developer is placed away from the photo conductor. On both sides of the developer, mutually cooperated gears are provided. One of the gear meshes with the drive gear with a clutch for driving the developer. The other gear is meshed with a brake gear coupled with a brake mechanism whose brake function can be turned On and OFF by control means, such as electric signal. The drive gear is arranged to urge the developer onto the photo conductor by rotation thereof. When the gear of the developer rotates, the brake gear is arranged at a position to urge the developer onto the photo conductor. The torque to start slippage of the brake is set at a value to be greater than a force of a spring pushing back the developer.
It should be noted that the gears on both sides of the developer, the drive gear and the brake gear may be replaced with a combination of the gear and the timing belt or other rotation transmitting means.